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bus: mhi: host: Drop chan lock before queuing buffers 

commit 01bd694ac2f682fb8017e16148b928482bc8fa4b upstream.

Ensure read and write locks for the channel are not taken in succession by
dropping the read lock from parse_xfer_event() such that a callback given
to client can potentially queue buffers and acquire the write lock in that
process. Any queueing of buffers should be done without channel read lock
acquired as it can result in multiple locks and a soft lockup.

Cc: <stable@vger.kernel.org> # 5.7
Fixes: 1d3173a3ba ("bus: mhi: core: Add support for processing events from client device")
Signed-off-by: Qiang Yu <quic_qianyu@quicinc.com>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Tested-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/1702276972-41296-3-git-send-email-quic_qianyu@quicinc.com
[mani: added fixes tag and cc'ed stable]
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Qiang Yu 2023-12-11 14:42:52 +08:00 committed by Greg Kroah-Hartman
parent 2df39ac8f8
commit 3c5ec66b4b
1 changed files with 4 additions and 0 deletions
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4
drivers/bus/mhi/host/main.c
View File

@ -643,6 +643,8 @@ static int parse_xfer_event(struct mhi_controller *mhi_cntrl,
mhi_del_ring_element(mhi_cntrl, tre_ring);
local_rp = tre_ring->rp;
read_unlock_bh(&mhi_chan->lock);
/* notify client */
mhi_chan->xfer_cb(mhi_chan->mhi_dev, &result);
@ -668,6 +670,8 @@ static int parse_xfer_event(struct mhi_controller *mhi_cntrl,
kfree(buf_info->cb_buf);
}
}
read_lock_bh(&mhi_chan->lock);
}
break;
} /* CC_EOT */